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When people think of diabetes, one of the first associations that comes to mind is food, and especially the old prohibition against eating sweets. In fact, today's dietary guidelines are not as stringent, but are slightly more complex. The guidelines are:
1. eat a variety of healthy, nutritious foods,
2. reduce fat and protein to reasonable amounts,
3. and balance carbohydrate with insulin and exercise.
Numbers 1 and 2 relate to good eating habits and discipline. Both are strongly encouraged for long-term health. Number 3 determines most of the blood sugar control related to eating. Half the day's insulin is used to balance the carbohydrate we eat in foods. (The other half meets the background insulin need, and this need remains relatively steady from day to day.)
Food contains carbohydrates, fats, and proteins as sources of energy, plus many other important ingredients like vitamins and minerals. The carbohydrates in food have the most impact on the blood sugar. High fat foods can contribute to obesity, heart disease, and higher blood sugars in the long run. However, dietary fat plays only a minor role in daily blood sugar control.
Protein is also a minor player in short-term control. Half the protein we eat is converted to carbohydrate over a period of several hours. But protein makes up only 10% to 20% of total calories, so it normally determines less than 10% of total control.
To measure the impact that carbohydrates have on the blood sugar, either the exchange system, counting calories, or the Total Available Glucose (TAG) system can be used. If one of these systems is working for you, don't change a thing. But if your blood sugars aren't in the normal range, this can be a great help. Carb counting specifically measures the upward drive each meal has on the blood sugar, and allows food to be accurately balanced with insulin or with exercise. Better control will result from knowing how much carbohydrate is in the foods you eat.
Control also depends on how quickly foods will raise the blood sugar. The Glycemic Index gives this value for a variety of foods.
What Are Carbs?
Healthy diets contain 50% to 60% of the day's total calories as carbohydrate. Carbohydrate comes from:
- grains (breads, pasta, cereals)
- fruits
- vegetables
- root crops (potatoes, sweet potatoes, and yams)
- beer, wine, and some hard liquors
- desserts and candies
- most milk products, except cheese
- -ose foods, like sucrose, fructose, maltose
Grams are a unit of weight like pounds or ounces. Because of their very small size (it takes 28 grams to equal a single ounce), grams can be used to accurately measure carbohydrate.
Covering Carbs With The 500 Rule
A good control program includes testing the blood sugar and using these readings in an organized way to adjust insulin doses. With your physician's help, your program whould first match doses of background insulin as needed to keep your blood sugar level while you are not eating.
For people on an insulin pump or using multiple daily injections, the 500 Rule in Table 1 can be used to estimate how many grams of carbohydrate will be covered by one unit of Humalog (lyspro) or Novolog (aspart) insulin.
For instance, the number of grams of carbohydrate covered by 1 unit of Humalog insulin equals 500 divided by the total daily insulin dose (TDD = an average of all long acting and short acting insulin used per day, or all basals and boluses typically used per day). For those using Multiple Daily Injections (MDI) or an insulin pump, this rule provides a good guide for how much insulin is needed to cover meal carbohydrates.
This rule cannot be used by those who are not using MDI or a pump. Because carbohydrates are not covered in each meal with Humalog or Novolog, the accuracy of the 500 Rule will be reduced because some of the long-acting insulin taken each day is used to cover the carbohydrate in meals.
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The 500/450 Rules
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500 Rule |
450 Rule |
| Total DailyInsulin Dose |
Grams of CarbCovered by1 Unit of
Humalog |
Grams of CarbCovered by1 Unit of
Regular |
| 20 |
25 |
23 |
| 25 |
20 |
18 |
| 30 |
17 |
15 |
| 35 |
14 |
13 |
| 40 |
13 |
11 |
| 50 |
10 |
9 |
| 60 |
8 |
8 |
|
Adapted from Pocket Pancreas, Copyright © 1994, Diabetes Services, Inc. |
Insulin Reaction Guides
These rules lets you match your meal carbohydrates with insulin for better post-meal readings. However, carbohydrates are also needed to raise a low blood sugar. For this, there are two helpful guides:
- One gram of carbohydrate raises the blood sugar about 3, 4, or 5 points for people who weigh 200 lbs., 150 lbs., and 100 lbs., respectively.
- The glycemic index, protein content, and fat content of foods can modify the speed and strength of Guide 1.
Example of Guide 1: Say you weigh 150 lb. and your blood sugar is 60 mg/dl. You plan to eat a meal in a half hour, but you want to raise your blood sugar to 100 mg/dl to be safe during this time.
To get a 40 point rise (from your current reading of 60 mg/dl to your target of 100 mg/dl), you'll need 40 points / 4 points per gram, or 10 grams of carbohydrate. Two Becton Dickinson Glucose Tablets have 10 grams of carbohydrate and would put you close to your target.
Example of Guide 2: Say you want to eat 15 grams of carbohydrate to correct a low blood sugar. If you use a fast carb like glucose tablets (glycemic index = 100), relief will be apparent in 10 to 15 minutes. If instead you use a slow carb like kidney beans (glycemic index = 33), relief may not be apparent for 2 or 3 hours, assuming your blood sugar has not dropped further during that time. Obviously, using fast carbs to raise low blood sugars is better.
How Many Carbs Do You Need Each Day?
Fill in the blanks to determine how many grams of carbohydrate you need each day.
1. First determine your desired weight in pounds:
a. If you are overweight, a 10% loss from your current weight is ideal.
desired weight = _______ lbs.
b. Or base your ideal weight on this formula:
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Women:
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100 lb. + |
5 X______ in. |
=
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________ lbs.
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| |
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inches over 5 ft. |
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your goal wt
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Men:
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106 lb +
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6 X ______ in.
|
=
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________ lbs.
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| |
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inches over 5 ft.
|
|
your goal wt
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Use this weight if you have an average frame.
- for a light frame, subtract 10% = ________ lbs.
for a heavy frame, add 10% = ________ lbs.
2. Choose a calorie factor that describes your
activity level:
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men
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women
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Very sedentary
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13
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11.5
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Sedentary
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14
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12.5
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Moderately active
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15
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13.5
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Active
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16
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14.5
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Super active
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17
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15.5
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3. Determine your total daily calorie need:
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_________ lbs
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X
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_________
|
=
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_________
|
|
desired wt.
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|
cal. factor
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cal/day
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4. Then divide by 8 (1/2 of calories as carbohydrate and 1/4 gram per calorie) to determine how many grams of
carbohydrate (CHO)you need each day:
| _________ |
/ |
8 |
= |
__________ |
| cal/day |
|
|
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grams of carb/day |
5. And last, decide how you want to split up this total daily
carbohydrate for different meals during the day.
| Breakfast |
______ grams |
| AM snack |
______ grams |
| Lunch |
______ grams |
| PM snack |
______ grams |
| Dinner |
______ grams |
| Eve. snack |
______ grams |
How To Count Carbohydrates
A few foods like table sugar and lollipops are entirely carbohydrate. When placed on a gram scale, their weight tells you immediately how many grams of carbohydrate they contain. But most foods have only part of their total weight as carbohydrate. The carbohydrate content of these other foods can be determined in three ways:
1. From Labels
Advantage: Very easy.
What you need: Food labels, occasionally a measuring cup.
How: Food labels contain all the information needed to do carb counting. Just be sure your serving is the same size as the serving on the label.
For example, the information to the right was found on a box of graham crackers.
The only confusing part comes in determining what is a serving of "4" crackers. Graham crackers come wrapped in cellophane with a rectangular shape. Each 2.25" by 5" rectangular cracker turns out to be 2 of the serving crackers, so one serving of "4" crackers is really 2 whole rectangular crackers. A serving has 22 grams of carbohydrate and will raise the blood sugar about 88 points.
2. From Books
Advantage: Great for eating out and an easy way to look up many brand name foods.
What you need: Books and occasionally measurements to determine serving size.
How: Information on the carb content in foods can be obtained from many helpful books:
Calories and Carbohydrates by Barbara Kraus; Penguin Books, New York, lists 8,000 foods.
The Carbohydrate Gram Counter by Corinne Netzer; Dell, New York, lists 10,000 foods.
Food Values by Jean Pennington, PhD, RD; Harper Collins, NY, comprehensive, many vitamins and minerals.
Total Nutrition Guide by Jean Carper; Bantam Books, NY, comprehensive: carbs, fats, minerals, fast foods.
Many cookbooks also have the carbohydrate content and exchanges listed with each recipe. These are great for preparing meals at home.
3. With A Scale
Advantage: Convenient for measuring carbs in odd-sized foods like fruits, unsliced bread, cereals, or casseroles.
What you need: A gram scale, a calculator, and a list of Carb Factors like those in Appendix A of STOP the Rollercoaster. A good gram scale will weigh between 1,000 and 2,000 grams in 1 to 2 gram increments and can be found at gourmet shops, medical supply stores, or at mail order suppliers like Nasco (1-800-558-9595)
How: To find the amount of carbohydrate a particular food has:
- Weigh the food on a gram scale to find its total weight in grams.
- Find that food's Carb Factor in one of the Food Groups.
- Multiply the food's total weight (grams) by its Carb Factor.
- This number is the number of grams of carbohydrate you are eating.
Examples:
Say you want to have a piece of French bread with dinner. You remove a piece from the loaf and place it on a gram scale. Your scale tells you it weights 80 grams. In Appendix A of STOP the Rollercoaster you find that the Carb Factor for bread is .50. (Meaning that 50% or half the total weight of bread is carbohydrate.)
You then multiply its weight (80 grams) by .50 to find out how much carbohydrate you will be eating:
80 grams of French bread X .50 = 40 grams of carbohydrate
You will be consuming 40 grams of carbohydrate from this French bread.
As another example, one gram of apple has 0.13 grams of carbohydrate, so 100 grams would have 13 grams of carbohydrate. Another way of saying this is that 13% of any apple's weight is carbohydrate (most of the rest is water).
We then know that 100 grams of apple will raise the blood sugar approximately:
13 grams x 4 points per gram = 52 points (unless countered with insulin or exercise)
The Carb Factors for a variety of foods have been listed.
How quickly do foods raise your blood sugar?
The glycemic index is a useful tool that measures how fast a particular food is likely to raise your blood sugar. It can be very helpful in managing your blood sugars. For example, if your blood sugar is low or it is dropping during exercise, you would prefer to eat carbohydrates that raise your blood sugar quickly. On the other hand, if you want to keep your blood sugar from dropping during a few hours of mild activity, you might prefer to eat extra carbohydrate with a lower glycemic index and longer action time. And if your blood sugar tends to spike after breakfast, you would want to select a cold cereal with a lower glycemic
index.
The numbers below are based on glucose, which is the fastest carbohydrate available except for maltose. Glucose is given a value of 100---other carbs are given a number relative to glucose. Faster carbs (higher numbers) are great for raising low blood sugars and for covering brief periods of intense exercise. Slower carbs (lower numbers) are helpful for preventing overnight drops in the blood sugar and for long periods of exercise. (Note: if you prefer to use white bread as your standard, simply multiply the numbers below by 1.42, i.e., glucose would have a glycemic index of
142.)
Note that these numbers are compiled from a wide range of research labs, and as often as possible from more than one study. These numbers will be close but may not be identical to other glycemic index lists. The impact a food will have on blood sugars depends on many other factors like ripeness, cooking time, fiber and fat content, time of day, blood insulin levels, and recent activity. Use the Glycemic Index as just one of the many tools you have available to improve your control.
ADA nutrition recommendations
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